1. Field of the Invention
The invention relates to thermally-insulated packaging, and more particularly to a packaging system with improved insulating characteristics for transporting perishables and the like.
2. Related Art
The shipment or transport of perishable materials frequently requires that such materials remain at a stable temperature which is either elevated or decreased with respect to ambient temperatures to which the packaging is exposed. Because of long transport times and/or sensitivity of certain contents to even slight temperature fluctuations, efforts have been made to provide shipping containers with improved insulating characteristics.
U.S. Pat. No. 4,889,252 to Rockom et al. suggests bonding of bubble-type insulation to an inner surface of a corrugated paperboard box to provide insulation and shock-absorbency. However, because of the direct contact of the bubble-type insulation with the paperboard, much of the potential thermal containment abilities of bubble-type insulation are subject to being undermined by the conduction of temperatures via the bubble-type insulation to or from the paperboard box and subsequently to or from the ambient atmosphere. The device according to Rockom et al. does not permit reuse of the insulating liner in other shipping containers when a first shipping container becomes worn. Further, the paperboard box of Rockom et al. is not fully collapsible once the insulation is bonded thereto.
Where extended shipping times and/or contents with extraordinary sensitivity to temperature fluctuations are involved, shipping containers with adequate insulating characteristics have not been provided by the prior art. Where contents requiring decreased temperatures are involved, it is often necessary to include a refrigerant, such as dry ice or gel packs, within the shipping container to maintain low temperatures, especially for extended periods of time. However, dry ice is expensive and considered hazardous by shipping handlers because of burning effects which are caused by its contact with the skin. Both dry ice and gel packs are relatively bulky, and their use therefore requires the use of a shipping container substantially larger than its primary contents. And, both means add substantially to the weight of the shipping container. Further, dry ice produces Carbon Dioxide gas, which is harmful if inhaled in high concentrations. For all of these reasons, national shipping companies, food service providers, caterers, pharmaceutical shippers, and others often charge an increased rate for shipping or transport of contents requiring temperature maintenance during transport.